Diamond has always been considered the hardest natural substance in the world. However, wurtzite boron nitride and mineral lonsdaleite have recently been discoverd and are much harder than diamond.
Dimonds are useful because its the hardest naturally occurring substace.
Diamond
Diamond.
The hardest naturally occurring substance is called diamond. It is a form of carbon.
A lubricant
Diamond :)
pure substace
diamond
A diamond
Yes.
Diamonds.